Continuity mistake: The taping of Rupert's monologue is done, and he's backstage eating crisps and talking with the FBI agent. The position of the packet in Robert De Niro's hand changes between shots, and when Gerrity asks "Where are we goin'?" his hands are not visible, but in the following shot they are fully in view as he is holding a pose. (01:13:00)
Continuity mistake: Masha is trying her knitwear on Jerry. When Rupert asks her to take it off him, Sandra Bernhard's arm position in the reflection does not match the following shot. (01:10:10)
Continuity mistake: When Jerry Lewis is kicking Robert De Niro and Diahnne Abbott out of the house, the delusional wannabe tells him "That's how you guys are, huh?", to which the late show star replies "No, not them, me." Suddenly in this shot the window door is closed, when it was not in the previous part of the scene. And at the next cut, Jerry is shown indeed closing the door. (01:00:25)
Continuity mistake: When Jerry Langford tells Rupert "If I didn't tell you that, we'd still be standing on the steps at my apartment" he is leaning into the golf club held in his right hand. Cut, and you can see the club jumped to his left hand, and after the Hitler joke, the club is back in his right hand. (01:00:00)
Continuity mistake: A lady at a payphone stops Jerry Langford and asks him to sign her copy of a magazine for her. He is doing it, and before he finishes, a lady with a beige hat walks past him. In the next shot the lady is followed by a guy that appeared suddenly. Likewise, the guy with green pants that was visible in the first shot moved into the next street, by the corner. (00:39:05)
Continuity mistake: Margo Winkler's receptionist character phones to Jerry's assistant to ask about that Rupert Pupkin fella who just showed up. When she tells him that there's no record of his appointment, she is holding the telephone in two different ways in the two separate shots. (00:26:50)
Continuity mistake: Rupert is waiting by the public phone. A line of people are angrily trying to shoo him away since the nearby phones are not working. You can see the various phone receives hanging down. But the one to the left in the closer angles is correctly hanged up as if the phone worked. (00:25:20)
Continuity mistake: During the conversation between Rita and Rupert at the counter of her bar (when she asks him what is he up to), the beer in his mug is slightly above/slightly below the handle as shot and countershot alternate. Likewise as the editing goes back and forth between those two angles De Niro is also touching the side of the glass with his finger or not. (00:15:50)
Continuity mistake: When Rupert in his dream is approached by a fan and asks her name (Dolores), Jerry Lewis has his left hand under his chin in the first shot, on the table in the next. (00:12:40)
Continuity mistake: On Rita's doorstep, Rupert says that he wouldn't want to impose. You can see Robert De Niro folding the jacket over his bag, but in the rest of the scene he holds the folded jacket between the bag and his body. (00:21:10)
Continuity mistake: When Masha reaches over to strip the tape off Jerry's mouth, look at the large duct tape cocoon he is wrapped into, in particular his lap. Later in the same scene when the crazy woman speaks to him it cuts to the same angle of the room (like when she says "Do you like these glasses?"), and you can see his constraints are different; there's a large visible strip of tape across his lap that was not there before. (01:19:00 - 01:19:45)
Continuity mistake: Masha reaches over with her left hand, but it is a right hand that removes the tape off Jerry's face in close-up. (01:19:00)
Continuity mistake: Rupert nonchalantly gets past the Asian butler Jonno and gives him his baggage and Rita's. He keeps to himself his 'work' briefcase, which is in his left hand as he says "No we'll just wait." There's a cut midsentence, and the object switched from left to right. (00:53:10)
Continuity mistake: After Sandra Bernhard has been removed, watch Jerry dive back into his car. One of the people aggressively seeking him, behind De Niro, makes a frustrated gesture with an open right hand. In the next shot (when it's Rupert to sneak into the car), the same person is holding a yellow notepad. (00:06:20)
Continuity mistake: Jerry Langford has just been kidnapped. He makes the first call to the network, but the receptionist hangs up on him. He then attempt again, but you can see him pick up the receiver twice in two separate shots. (01:05:50)
Continuity mistake: In the country home, after Rita walks away, Jerry Langford walks Rupert out of the room, telling him he just wanted to get rid of him when he told him to call his secretary. During the scene, Jerry Lewis is leaning against the door in some shots and suddenly isn't at the cut. (01:00:05)
